Police traffic surveillance devices emit an electromagnetic signal in the radio frequency (RF) band or light band (i.e., infrared, visible, and ultraviolet light) that reflect off of approaching or departing vehicles to determine their speed. In particular, a change in frequency (Doppler shift) or a change in time of travel for return signal pulses is sensed for calculating vehicle speed.
Police radar and laser detectors (“detectors”) are used by drivers of vehicles to detect radiant electromagnetic signals characteristic of police traffic surveillance devices. In particular, the following RF (radar) frequency bands are used: X-band (10.525 GHz±25 MHz); K-band (24.150 GHz±100 MHz); and Ka-band (34.700 GHz±1300 MHz). Furthermore, laser wavelength of 904 nm with 33 MHz bandwidth is also used. These detectors are generally a detachable device clipped to a visor or dash of the vehicle for unimpeded sensing of the signals and for providing a conveniently positioned display and one or more controls to the driver. While police radar/laser detectors successfully provide alerts to the driver, generally during significant portions of time there are no alerts to be made. Consequently, the display capabilities of the detector are generally limited to displaying the operating mode (“pilot mode”) of the detector. In addition to the under-utilized display, detectors increasingly use digital signal processors for processing received electromagnetic signals that operate faster with additional data and program storage capabilities. Consequently, the processing capacity of the detectors is also under-utilized much of the time. For example, detectors spend less than two percent of their operating time alerting the user of received electromagnetic signals.
Taking advantage of the unused capacity of a detector would increase its value. For instance, many drivers would benefit from the display of other sensed conditions associated with their vehicle. However, sensor displays integral to the vehicle instrument panel are either expensive or unavailable for certain models. Using after-market displays is inconvenient and tends to clutter the interior of the vehicle. Consequently, drivers often forego incorporating additional displays for sensed conditions.
Most cars and light trucks on the road today have on-board diagnostic (OBD) systems. In an effort to met Environmental Protection Agency (EPA) emission standards, manufacturers started using electronic engine management to control engine functions and diagnose engine problems during the 1970's and early 1980's. Through the years, on-board diagnostic systems came into being and have recently become more sophisticated. OBDII, a standard introduced in the mid-1990's, provides almost complete engine control and monitoring of other parts of the vehicles including the chassis, body and accessory devices, as well as providing a diagnostic control network for the vehicle.
The origin of these systems dates to 1966 when, in an effort to reduce smog in the Los Angeles Basin, the State of California began requiring emission controls on 1966 model cars. Later, in 1968, the federal government extended these controls nationwide. In 1970, Congress passed the Clean Air Act and established the Environmental Protection Agency (EPA). In doing so, Congress charged the EPA with reducing emissions from cars and trucks. The EPA then promulgated a series of emission standards for motor vehicles to meet this mandate. These standards were graduated, becoming ever more stringent on vehicle emissions with time. Further, manufacturers were required to maintain the vehicle within the emission standards for the useful life of the vehicle.
Manufacturers, in an effort to meet these standards, introduced electronic engine management systems that control engine ignition and fuel delivery. These systems included sensors for monitoring various engine parameters. The ignition and fuel delivery are adjusted based on sensor readings so that vehicles comply with the emission standards. Access to these sensors for diagnostic purposes was also provided.
In the beginning each automotive manufacturer had its own engine management system and used signals commensurate with their system. Finally, in 1988, the Society of Automotive Engineers (SAE), established a set of standards for a connector plug and a set of diagnostic test signals. The EPA adapted most of these standards established by the SAE regarding on-board diagnostic programs, as well as some other recommendations. OBDII is an expanded set of standards and practices developed by SAE and adopted by the California Air Resources Board (CARB) and the EPA. The deadline for implementation of OBDII was Jan. 1, 1996.
Manufacturers began incorporating OBDII standards into various models as early as 1994, although some of these early vehicles were not completely compliant with OBDII standards. However, all vehicles manufactured since Jan. 1, 1996 are compliant with the OBDII standard. OBDII provides a universal inspection and diagnosis method to ensure the vehicle is performing to original equipment manufacturer (OEM) standards. A scanner console or tool is connected to the OBDII connector to inspect and diagnose the vehicle.
There are currently three basic protocols in use, each with minor variations on the communication pattern between the on-board diagnostic computer and the scanner console or tool. While there have been some manufacturer changes between protocols in the past few years, as a rule of thumb, Daimler Chrysler products and all European and most Asian imports use International Standards Organization (ISO) 9141 circuitry. General Motors uses SAE J1850 VPW (Variable Pulse Width Modulation), and Ford Motor Company uses SAE J1850 PWM (Pulse Width Modulation) communication patterns.
It is also possible to tell which protocol is used on a specific automobile by examining the dash connector socket. If the connector has a pin in the #7 position and no pin at #2 or #10, then the vehicle has the ISO 9141 protocol. If no pin is present in the #7 position, the vehicle uses a SAE protocol. If there are pins in positions #7 and #2 and/or #10, the vehicle may still use the ISO protocol. While there are three OBDII electrical connection protocols, the command set is fixed according to the SAE J1979 standard.
Pre-OBDII cars had connectors in various positions under the dashboard and hood. However, as part of the standard, all OBDII vehicles have a connector located in the passenger compartment, easily accessible from the driver's seat. Often, the connector is located under the dash or behind or near the ashtray. A cable is plugged into the OBDII J1962 connector and connected to a scanner console or scan tool. This equipment ranges from a simple hand-held meter that provides a coded readout of the various diagnostic functions, up to a large console computer-based unit costing thousands of dollars.
These large units are compatible with all cars and contain software that analyzes the signals received from the car, displays a text or diagrammed readout of any malfunctions found and suggests possible solutions to the problems.
Smaller units for the home or small shop technician can provide a variety of levels of data, some approaching the sophistication of the big shop consoles. However, they are usually limited to one OBDII system type, unless adapters can be purchased.
OBDII signals are most often sought in response to a “Check Engine Light” appearing on the dashboard or driveability problems experienced with the vehicle. The data provided by OBDII can often pinpoint the specific component that has malfunctioned, saving substantial time and cost compared to guess-and-replace repairs. Scanning OBDII signals can also provide valuable information on the condition of a used car.
There are other methods to gather data from a vehicle other than using OBDII. One method involves the development of the Intelligent Vehicle Data Bus (IVDB). The IVDB allows all computers within a vehicle to communicate with each other, and potentially makes data used or held by those computers available across the IVDB.
Therefore, a significant need exists for a police radar/laser detector that incorporates additional sensing and display of conditions associated with a vehicle, as well as other vehicle data such as that gathered using an on-board diagnostic system or intelligent vehicle data bus.